Yellow monoazo dyestuff and process of making same.



UNITED STATES Patented June 23, 1903.

PATENT OF ICE.

WALTER DOLLFUS AND RUDOLF HAGENBAOH, OF HGOHST-ON-THE-MAIN, GERMANY, ASSIGNORS TO FARBWERKE, VORM. MEISTER, LUCIUS & BRl lNlNG, OF HOCHST-ON-THE-MAIN, GERMANY, A CORPORATION OF GE R-MANY.

YELLOW MONOAZO DYESTUFF AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 731,670, dated June 23,1903.

I Phenylmethylpyrazolon, of which the follow- 1o ing is a specification.

By combining diazotized ortho-amido-parasulfobenzoic acid with phenylmethylpyrazo- 1011 a yellow azo. dyestuff is obtained which is particularly suited for the manufacture of ini 5 soluble yellow color-lakes fast to water, acid,

lime, and light, especially as regards the latter, if compared with the anilin dyestuffs hitherto used for this purpose.

The manufacture of the new dyestuff is ac illustrated as follows:

Example: The diazo compound obtained from 21. 7 kilos of ortho-amido-para-sulfobenzoic acid. in the usual manner with hydrochloric acid, and nitrite isgradually run into 25 a solution of 17.5 kilos of phenylmethylpyrazolon in the equivalent quantity of causticsoda lye and in presence of fifteen kilos of sodium carbonate.

The dyestuff separates at once as a Viscous o yellow mass, which on the reaction being Application filed April 11, 1903. Serial No. 152,119. (No specimens.)

complete is precipitated by boiling with common salt and then dried.

When dry, the dyestuff is a yellow powder, soluble with difficulty in cold and readily soluble in hot water.

Having now described our invention, what we claim is- 1. The herein described process for the manufacture of a yellow monoazo dyestuff specially suited for preparing color-lakes fast 0 to light and for dyeing paper which consists in combining diazotized ortho-amido-parasulfobenzoic acid with phenylmethylpyrazolon, substantially as set forth.

2. As a new product the monoazo dyestuif 4 5 obtained by combining diazotized ortho-amido-para-sulfobenzoic acid with phenylmethylpyrazolon, being when dry a yellow powder, soluble with diificulty in cold and readily soluble in hot water and specially suited for 50 preparing yellow insoluble color-lakes fast to water, acid, lime, and light.

In testimony that we claim the foregoing as our invention we have signed our names in presence of two subscribing witnesses.

WALTER DOLLFUS. RUD OLF HAGENBACH.

NVitnesses:

ALFRED BRIsBoIs, BERNHARD LEYDECKER. 

